Does E-mail Inbox has performance issue?

Hello Experts,

I have configured E-mail Inbox in CRM Web UI. After clicking on the E-mail Inbox link, Its taking a minimum of 15 to 20 minutes, some times its taking more than that, in the meanwhile webui session goes timed out, .

Can we increase the performance to import emails quickly or will it depend on number of emails in the Lotus Notes? If in case it depends on the number of emails in the Lotus Notes, for importing 500 mails, approximately how much time should it take?

Thanks in advance.

Rohan